Engine starter gearing



Julie 27,1939. D. P. KEARNEY 2,163,341

ENGINE STARTER GEARING Filed Aug. :51. 195'! E2 Sheets-Sheet 1 June 27, 1 939. D, P, K E I 2,163,841

ENGINE STARTER GEARING Filed Aug. 31, 1937 i2 Sheets-Sheet z 1 v I v l lqwq 'lunnunniiudun INVENTOR TTTMUVEK rmm'zzlaee mun-:1) STATES PATENT OFFICE mus 1r. leaner.

meme sun-11in Gas-mo signer hflelnemtolleallxbvlafloncor- South Ball-l, a corporation A e :1, 1931. 8erlal on... 101.19,

7 sou-.- 'lhepresentinventionrelatestoenginestarter" g'earinsandn oreparticularlytoatnnsmlsslon a mina IWQIBII enalne-tobestarmandplissan erwhen the engine beoomes selteover tive-r Insur n o the't p indicated, it is desirable tomrqviide means for pveventin'; the premature of the gearing oeeasioned 1o tying; bar abortive start of the 111 asn'ipch as ensaaement or the gearing is dependeat on of the starting motor,

' flier h motor he deenergized and allowed to come it is posandrenew the.

r tasted the engine. This is time-eon.-

h flming il d pnlfltstheenainetoeometoa qrm sor lo eratiop whioh amm flm disadvantageous.

Itis s cbfiedt ofthenresent inventiohto provide noyelstartergearln'gottheautqmaticmesh whe e tland adun ueswm sapi drawings-in Wm emhodiment of the inveqflgrjfllnsisi'reelyj mrnalledonthepowershattlforlongiwith omemhersnehasa flywheei gear" of rzg flgfi isidrnilarrlewshowlngtheparhin. f r

m provkled'for limitingthe Referring first tom. 1 of the drawings, there is illustrated a power shaft l whlchmay be the extended armature shaft of a starting motor, not illustrated. A hollow shaft lis fixedly mounted on the power shaft I by any snitable meanssuch as'akey Landaserewsha'ft l islfreelyjonrnailed on the hollow shaft 2, being retained thereonbysuitabiemeanssmhasastopnut i.

ll'eans'for yleldably driving the screw shaft 4 nortlonllol'thesorewshaft.

in the format a pinion l2 he started.

and II (163. 5) II and control not ll respetlvely, the mem ber'lIhelng'non-rotatablyeonneetedtotheharr l. ammo: lugs ll on'the barrel traversing openings am the a retl'ininzsnrincwlrellseatedinmplemmtar -w "and I5 inthe'elutdl member and WWW-L the 56- form-of a ring or thimble 28 mounted on the control nut i4 and having a lock ring 21 seated in the interior thereof in position to engage the rear face of the clutch member I5. i

In order to prevent ebounding of the pinion into engagement with the engine gear after being demeshed therefrom, the threads of the screw shaft 4 .are preferably terminated adjacent the idle position of the control nut i4, forminga smooth portion 28 (Fig. 2) on the screw shaft on which the control nut may rotate freely when in. idle position. Means in the form of a compression spring are provided for causing the control nut It to enter the threads of the screw shaft when the screw shaft is accelerated by the starting motor.

Means in the form of a light compression spring 3|- mounted in the barrel l6 between the stop nut 5 and theclutch member I5 are provided for urging the pinion and barrel assembly -toward idle position and preventing it from drifting toward cranking position during opera- .tion of the en e.

In the operation of the starting mechanism as so far described, acceleration of the screw shaft 8 by means of its connection to the power shaft I when the starting motor is energized causes the control nut 14 to thread itself along the screw shaft into the position illustrated in Fig. 2, causing the driving pinion I! to mesh with themgine gear l3. When the longitudinal movement of. the control nut I4 is stopped by the stop nut 5, the parts are all connected for rotation from the power shaft I through the spring 6 and overrunning clutch member 'I 5, whereby the pinion l2 the interior of the barrel l6 as by means of a spring 35. g The interior of the barrel I6 is provided with' a spiral groove 31 of suitable low pitch in which the nose of the latch 34 is adapted to engage when the pinion is moved toward operative position as illustrated in Fig. 2. The barrel I6 is formed with a smooth portion 38 for receiving the latch 34 when the barrel is in idle position so as to permit the barrel and pinion assembly to then overrim freely.

In operation, during the meshing movement of the pinion and barrel assembly by the traversal of the control'nut M on the screw shaft, the latch 34 ratchetsover the 'convolutions of the spiral groove 31 without interfering with the meshing movement of the pinion l2. When an explosion occurs in the engine, the acceleration 'of the driving pinion l2 by the flywheel gear causes the pinion and barrel assembly tooverrun the screw shaft, whereby the control nut I4 is caused to back away as previously described.

is rotated to crank the engine. It will be noted that at this time the clutch member I5 is clamped tightly'against the control nut l4 by reason of the engagement of-the flange 32 on the clutch member I5 against the thrust washer 33 which 1 is seated against the stop nut 5. The pitch of the threads of the screw shaft and control nut is comparatively steep so as to cause the driving pinion to be meshed with the engine gear by the initial rotative movement of the screw shaft, and, to avoid wedgiim or looking up of the pinion in driving position.

when the engine starts, the acceleration of the engine gear 13 due to the self-operation of the engine causes thepinion l2 to overrun the starting motor whereby the control nut I4 is rotated the barrel l6 faster than the screw shaft 4, causing it to back away from the clutch member I5 and permit the pinion, barrel and clutch member to overrun. If the engine contlnues'to beself-operative, the overrunning action'of the pinion and barrel assembly, td-

gether with the expansion of'the return spring 3| causesthe control nut l4 to be moved back on the screw shaft 4 to its idle position where it rotates freely on the smooth portion 28 of the screw shaft untilthe parts come to rest.

According to the'present invention, means are provided for positively. maintaining the pinion I: in engagement with the engine gear I! until the pinion has been caused to overrun the starting motor a. predetermined number of revoiu- I tions, thus preventing disengagement or the gearing due to. a false or abortive start of the engine, and permitting such disengagement only in case ofa true initiation of self-operation of theenginet Ashereillustratedthismeansisinthe form of' alatch member 34 hinged to the-stop nut 5 at II and yieldingly urged-against The latch 34 prevents immediate withdrawal of 4 the pinion I2 so'that the control nut l4 moves away from the clutch member l5, thus permitting the pinion and barrel assembly to overrun the control nut. If the engine continues to operate under its own power, the barrel l6 continues to overrun and thread itself back on the latch 34 until after a predetermined number of revolutions the pinion I2 is completely demeshed from the engine gear. If, however, the start of the is discontinued before the predetermined number of revolutions-has been accomplished, the slowing down of the pinion and barrel assembly engine should be abortive so that the overrunning action of the pinion and barrel assembly will permit the control nut to pick up the clutch member l5 and cranking is resumed as soon as the starting motor catches up with the engine speed. It will be understood that the pitch of the spiral groove 31 in the barrel" is so selected that the predetermined number of revolutions necessary for demeshing the driving pinion is such as to effectively distinguish between a false and a true start of the engine.

"-In Fig. 5 an optional somewhat simplified form of overrunningclutch connection between the "control nu-t 4| and overrimning clutch member 42 is provided. In this case the engaging clutch surfaces are coned slightly, the control nut 4| is mounted within the barrel 43, being retained therein by a lock ring 44, and the connection between the clutch member 42 and the barrel is effected by means of radial lugs 45 on the clutch member extending into grooves 46 in the barrel.

In Fig. 6 the structure is substantially similar to Fig. 5 except that the engaging surfaces of the control nut 4| and clutch member 42 are formed without serrations, the necessary frictional driving connection being effected by the selection of a" suitable angle of inclination of these surfaces to the axis of the drive.

In Figs. 5 and 6 a plurality of latches 34 are illustrated,-which latches may, as shown, he in stepped relation with respect to the spiral groove 31 so as toreduce the amount of lost motionbetween the barrel and stop nut.

Although certain forms of the invention have been shown and described in detail, itwill be understood that other forms are possible-and various changes may' be made in theidimensions and arrangements of the parts without departing from the spirit of the invention as defined in the claims appended hereto.

What is claimed is member, said connecting means including an overrunning clutch, and detent means for preventing disengagement of the driving member from the engine member until the driving member has overrun the power member for a predetermined number of revolutions, said detent means being arranged not to interfere with the engaging movement of the driving member.

2. In an engine starter drive, a power shaft, a pinion freely mounted thereon for movement into and out of engagement with a member of an engine to be started, means including a threaded connection of high pitch and an overrunning clutch for moving the pinion into operative position and rotating the same, and means including a spiral connection of low pitch between the pinion and power shaft for maintaining the engagement of the pinion with the engine member until the pinion overruns the power shaft a predetermined number of revolutions.

v3. In an engine starter drive, a power shaft, a pinion freely mounted thereon for movement into and out of engagement with a member of an engine to be started, means including a threaded connection of high pitch and an overrunning clutch for moving the pinion into operative position and rotating the same, and means including a ratchet connected to the power shaft and having a spiral connection or low pitch with the pinion for maintaining the engagement of the pinion with the engine member until the pinion overruns the power shalt a predetermined number of revolutions. a

4. In an engine starter drive, a screw .shaft, a control nut threaded thereon, a stop member limiting longitudinal movement of the control nut, a drive pinion, connecting means whereby longitudinal movement of the control nut moves the pinion into and out of engagement with a member of an engine to be started, an overrunning clutch between. the pinion and controlnut, and means on the stop member cooperating with the connecting means to prevent movement of the pinion out of engagement with the engine member until the pinion has overrun the. control not a predetermined number 0! revolutions.

5. In an engine starter drive, a screw shaft, a control nut threaded thereon, a stop member limiting longitudinal movement of the control nut, a drive pinion, connecting means whereby longitudinal movement of the control nut moves the pinion into and out of engagement with a member of an engine to be started including a barrel member, an overrunning clutchbetween the barrel member and control nut, and means on the stop member cooperating with the barrel member to prevent movement of the pinion out of engagement with the engine member until the pinion has overrun the control nut a predetermined number of revolutions.

' 6. In an engine starter drive, a screw shaft, a control nut threaded thereon, a stop member limiting longitudinal movement of the control nut, a drive pinion, connecting means whereby longitudinal movement of the control nut moves thepinion into and out ofgngagement with a member of an engine tobe started including a barrel member, an overrunning clutch between the barrel member and control nut, said barrel having a spiral groove, and a latch on said stop member engaging in said spiral groove to hold the pinion in engagement with the engine member until the pinion has overrun the control nut a predetermined number of revolutions.

7. In an engine starter drive, a driving member, means for traversing the driving member into and out of engagement with a member of an engine to be started and for rotating the same, and means independent of said traversing means including a latch member having a spiral connection with the driving member for preventing withdrawal of the driving member Irom the engine member until the driving member has overrun the latch member a predetermined number of revolutions. V

8. In an engine starter, a power shaft, a pinion slidably journalled thereon, means for sliding the pinion into and out of mesh with a member'ot an engine to be started, means including an overrunning clutch for connecting the pinion for rotation by the power shaft, and detent means preventing disengagement oi the driving member from the engine member until the driving member has overrun the power shaft a predetermined number or revolutions. 

